The Mechanics Behind Trigger Finger

Trigger finger, or “stenosing tenosynovitis” can often occur without experiencing a single injury. The causes of this condition are not well known, but symptoms may begin after exhausting your hand by pinching or grasping for an extensive period of time. This condition is also common in older individuals and in those with medical conditions, such as diabetes and rheumatoid arthritis.

Trigger finger is a common condition, which can be quite disabling. Common symptoms include swelling and pain in the palm, and catching or locking of the finger with attempted motion. What allows your fingers to bend are the flexor tendons that attach the muscles of the forearm to the bones of your fingers. Each of these long cord-like tendons pass through a tunnel (tendon sheath) in your palm and fingers, allowing the tendon to glide smoothly as the finger bends and straightens. Bands of tissue called “pulleys” hold the flexor tendons closely to the finger bones. The pulley located at the base of your finger is called the “A1 pulley,” and this is the pulley that can become inflamed and cause your trigger finger.

When the A1 pulley becomes inflamed or thickened, the flexor tendon has a hard time gliding smoothly and allowing your finger to bend and flex. What can cause the sensation of your finger popping or catching is when the flexor tendon develops a small nodule on its surface from inflammation. The nodule makes it difficult for the tendon to pass through the pulley, causing pain and discomfort. This nodule is also what can cause your finger to get stuck, requiring you to use your other hand to straighten the finger.

Treatments that you can attempt at home include stretching, massage, heat, and oral and/or topical anti-inflammatories.  If these fail to improve your symptoms, it is time to see a physician for more treatment.  Hand specialists often start with steroid injections and splinting, but sometimes trigger finger requires orthopedic surgery for definitive treatment.